Seth on dates:

One of the most expensive things a service business or freelancer can do is promise that work will be done by a certain day. Which is something we need to do, of course, but we should charge appropriately. “It’ll be done soon,” should be way cheaper than, “It’ll be done at exactly 11 am on Tuesday.”

And one of the most important things we can do to focus our energy and commitment is be prepared to promise a date certain. It sharpens everything.